The atmosphere surrounding Earth is full of air! The air in our atmosphere is made of molecules of different gases. The most common gases are nitrogen (78%) and oxygen (about 21%). There are other types of air molecules as well, but in very small quantities. Air is important for almost all life on Earth including plants and animals. Plants need gasses from air to do photosynthesis. Animals need to breathe air to get the oxygen they need to survive.
Is it important that we have this exact mixture of nitrogen and oxygen?” Yes, I can assure you it is most important. If the nitrogen were increased, our life processes would slow down and we would die. If the oxygen were measurably increased, our life processes would be rapidly increased. Our pulse rate would just run away and soon we would wear out and die. But God made it just right. Suppose, for example, it was two-thirds nitrogen and one-third oxygen. If that proportion prevailed, and an electrical reaction caused the elements to combine, do you realise that the whole world would be turned into laughing maniacs? Everybody would be laughing because that would produce the laughing gas, N20, the same kind dentists sometimes use when extracting teeth. Or, suppose it was divided half and half. That would produce nitric oxide, which is quickly fatal to all forms of life. Was it just a lucky accident that it came out like this? Did some blind happenstance of nature produce this exact mixture that is necessary for life support? Or, was there an intelligent design? This world would become chaotic if this atmospheric mixture slipped out of control for just a single instant. We would see one of the most tremendous of all explosions, because nitrogen is the basic component of gunpowder; and oxygen, of course, makes for rapid combustion. It would be “Goodbye, world!”
God has ensured mechanisms are in place to maintain the stability of the oxygen level, in spite of fluctuations in the amount released into or drawn from the atmosphere. In the real world, the level of oxygen is indeed maintained in an excellent balance, becoming neither too low nor too high.
Categories: Earth
Feed My Sheep 
“But the day of the Lord will come like a thief. The heavens will disappear with a roar; the elements will be destroyed by fire, and the earth and everything in it will be laid bare.” 2 Peter 3:10 NIV 11984. I have often wondered how exactly that would happen, but it looks like the atmosphere already contains all the right ingredients.